Roof assembly

ABSTRACT

A roof assembly includes a frame having primary beams, secondary beams mounted transversely on the primary beams, and a ceiling grid suspended from the secondary beams. A method of assembling the roof assembly includes assembling the primary beams over the ceiling grid and connecting the secondary beams to the primary beams. The assembly is assembled on the ground and lifted to a fully installed position using a transportable lift.

BACKGROUND OF THE INVENTION

The present invention relates to roof assemblies and a method ofinstalling a roof assembly to form the roof of a building such as afactory or commercial building.

Normally a building is constructed by installing the foundations andfloors, constructing a framework for the walls and roof, and theninstalling the elements which make up the walls, ceiling and roofing,The plumbing and wiring are usually installed once the shell of thebuilding has been constructed.

Typically, the roof of a building in particular is constructed in situ,that is, above the ground. Constructing anything above ground level addsto the cost of construction.

Where buildings have been required in locations having high constructioncosts, they have been fabricated in modules that have been transportedto the site and assembled in situ thereby considerably reducing the costof labour required at the site. However, to be transportable suchmodular buildings have lacked aesthetic appeal and when the high cost oftransport is taken into account, have not been competitive in situationswhere construction labour is readily available.

Because the roof of a building is largely assembled above the ground itusually represents a disproportionately high component of the total costof construction. There is therefore a considerable economic advantage tobe obtained by assembling a roof on the ground and lifting it intoposition as a unitary structure.

Patent application Ser. No. 22914/77 describes a prefabricated roofstructure having an underlying peripheral support to provide rigidity sothat the structure can be raised as a unit. The prefabricated structuredescribed includes roof trusses, fasica, guttering and rafters. Thestructure is supported at a level slightly above the ground while tilingor roof sheeting is applied to the frame. The structure is then raisedso that the ceiling and soffits can be readily fitted from ground level.The roof structure may be raised by hydraulic or mechanical jacks orcranes according to circumstances.

The proposal described in patent application Ser. No. 22914/77 suffersfrom a number of disadvantages. Firstly the roof is so designed that itis necessary to add a peripheral support to provide rigidity. Theadditional materials and time required to construct the support add tothe cost of the structure. Secondly the multi-lift assembly of thestructure, adds to the cost and increases the risk of accidents arisingespecially while the ceiling is being installed. An objective of thepresent invention is therefore to reduce the cost of constructing andinstalling building roofs and overcome the problems associated withprevious proposals.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides a non-transportable roofingassembly for a new building comprising a frame, roof cladding elementsand ceiling elements but no additional peripheral support structure, theroofing assembly being specifically designed to be assembled on theground and lifted into position as an assembly using transportablelifting means.

The assembly design takes account of lifting rigidity, total weight,location of lifting points, type of lifting means to be used, stabilityduring erection, securing and safety.

In another aspect of the present invention there is provided a method ofconstructing a building roof comprising designing a footing assembly tobe assembled on the ground and lifted into position using transportablelifting means, constructing a roof frame on the ground near a buildingto be roofed using elements having a high strength to weight ratio,installing ceiling and filing elements on the frame to form a roofassembly, lifting the roof assembly into position using transportablelifting means, and securing the roof assembly to load bearing columnsforming part of said building.

The transportable lifting means may comprise one or more chain blocks ormobile cranes.

If chain blocks are to be used to raise the assembly into position, theassembly will be constructed directly below its installed position.Power for the chain blocks may be supplied from the power linesinstalled within the assembly. Once the roofing assembly has been raisedto its installed position, the primary beams can be bolted toneighbouring load bearing columns.

The roof frame may be formed from primary beams made from universalbeams, channels or cold rolled Z sections and secondary beams or purlinsformed from c or z metal cold rolled sections. The primary beams may bespaced such that the distance between them lies in the range between 4and 12 meters. The secondary beams may be spaced such that the distancebetween them lies in the range from 0.3 to 2 meters. The roof claddingelements may be any metal deck such as for example, Lysaght Brownbuilt"Trimdek". The ceiling elements may be "Rondo" or similar suspendedceiling grids having plaster ceiling tiles.

Preferably the roof ash a pitch of less than 10 degrees.

Preferably also, electrical wiring, lights, gutters, skylights, vents,fascias, insulation and any ducting are installed prior to lifting theroofing assembly into position.

A particularly preferred method of constructing a roof according to thepresent invention comprises the steps of:

(1) laying out primary beams and a ceiling grid,

(2) installing load bearing columns,

(3) positioning the primary beams,

(4) assembling the ceiling grid,

(5) fixing purlins to the primary beams to form a frame,

(6) connecting the ceiling grid to the purlins,

(7) installing electrical wiring and lights,

(8) dropping ceiling panels into position,

(9) fixing roof cladding to the frame and installing insulation,

(10) installing gutters, skylights, vents and fascias,

(11) preparing lifting points.

(12) lifting the roofing assembly into position on the load bearingcolumns using chain blocks or mobile cranes,

(13) securing the roofing assembly to the load bearing columns,

(14) bracing the load bearing columns to improve their load bearingcapacity,

(15) removing the chain blocks or mobile cranes and

(16) finishing off around the load bearing points.

Ideally the method of the present invention forms part of a method forvery fast building construction. This preferably involves the off-siteconstruction of service room modules such as kitchens, bathrooms andtoilets for subsequent installation in the building in a completelyassembled state. Typically such a method involves the following steps:

(1) constructing foundations,

(2) forming a concrete slab,

(3) installing load bearing columns,

(4) constructing a roof according to the method of the present inventionsimultaneously with the preceding steps,

(5) installing service modules constructed off-site,

(6) constructing external and internal walls, and

(7) completing fit-out and finishing off.

Preferably very fast building construction also includes utilization inthe pre-construction period of an integrated site management system.Such a system involves testing and assessing a construction site,preparing the site ready for construction, certifying the site forparticular types of construction and maintaining it ready forconstruction. This system is more particularly described in co-pendingpatent application Ser. No. PJ8340.

BRIEF DESCRIPTION OF THE INVENTION

FIG. 1 is a perspective view of a concrete slab having a polyethylenesheet and primary beams positioned thereon;

FIG. 2 is a perspective view of the concrete slab, polyethylene sheetand primary beams according to FIG. 1 and further including a ceilinggrid;

FIG. 3 is a perspective view of the roof assembly according to FIG. 2,and further including lighting and ventilation points;

FIG. 4 is a perspective view of the roof assembly according to FIG. 3,and further including load bearing columns;

FIG. 5 is a perspective view of the roof assembly according to FIG. 4,and further including secondary beams;

FIG. 6 is a perspective view of the roof assembly according to FIG. 5,and further including extension, chain blocks and a control box;

FIG. 7 is a perspective view of the roof assembly according to FIG. 6 inthe erected position; and

FIG. 8 is a construction schedule.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 depicts a concrete slab 1 having a sheet of polyethylene 2 placedover its upper surface. Primary beams 3, 4, 5 and 6 are then laid outacross the polythene 2 placed. Primary beams 3, 4, 5 and 6 may be laidout across the concrete slab with a clearance of about 50 mm from theupper surface of the slab 1.

FIG. 2 depicts a ceiling grid 7 laid out between the primary beams 3, 4,5 and 6. The 50 mm clearance enables the ceiling grid 7 to be laid outunder the primary beams. Lighting points 8 and ventilation points 9 areinserted in the ceiling grid as shown in FIG. 3 Ceiling tiles may beinstalled at this stage or after the roof has been raised. Load bearingcolumns 10, 11, 12, 13, 14, 15, 16 and 17 are installed in the slabadjacent to the ends of the primary beams (FIG. 4).

FIG. 5 depicts the concrete slab, the primary beams and the load bearingcolumns without the ceiling grid and attached lighting and ventilationpoints. Purlins or secondary beams 18 are laid out in a directiontransverse to the primary beams 3, 4, 5, 6. The secondary beams areconnected to the primary beams and the ceiling rid is connected to thesecondary beams.

Ideally gutters, gutter boards and wiring (not shown) are installed atthis stage. All fascias 25, (FIG. 7) flashings, gutters, skylights,vents, services and other installations are completed ready forelevation of the roof.

The load bearing columns, 10, 11, 12, 13, 14, 15, 16 and 17 are extendedby means of extension 20 and chain blocks 19 are attached to the top ofthe extensions as shown in FIG. 6. The electric chain blocks 19 arecontrolled from a central control box 21 and the roofing assembly raisedto its erected position as shown in FIG. 7.

FIG. 7 depicts the roofing assembly 22 in its erected position. The roofhas a ridge line 23 and a pitch of less than 10 degrees. Bracing 24 isinstalled between columns 15 and 16 and columns 11 and 12 (not shown).

It will become apparent to those skilled in the art that variousmodifications to the preferred embodiment described and disclosed hereincan be made. Such modifications will be considered as within the scopeof the claims appended herebelow unless such claims by their languageexpressly state otherwise.

I claim:
 1. An integrated roofing assembly for a new building, theassembly comprising:a ceiling grid assembled on the ground at aconstruction site and adapted to support ceiling tiles; a frame, saidframe including primary beams positioned on said ceiling grid andarranged parallel to each other, and secondary beams positioned on andconnected to said primary beams and arranged transversely to saidprimary beams, said ceiling grid being located beneath said frame andbeing connected to said secondary beams, and said frame having liftingpoints; roof cladding elements coupled to said frame, said primary andsecondary beams acting together to structurally support said roofcladding elements; whereby said roofing assembly is assembled on theground as an integrated unit without additional peripheral supportstructure for lifting into a fully installed position usingtransportable lifting means removably coupled to said lifting points. 2.An integrated roofing assembly according to claim 1 wherein said primarybeams are selected from a group consisting of universal beams, channelsand Z cold rolled metal sections.
 3. An integrated roofing assemblyaccording to claim 1 wherein said secondary beams are formed from C or Zcold rolled metal sections.
 4. An integrated roofing assembly accordingto claim 1 wherein said primary beams are spaced apart by a distance ina range from 4 to 12 meters.
 5. An integrated roofing assembly accordingto claim 1 wherein the secondary beams are spaced apart by a distance ina range from 0.3 to 2 meters.
 6. An integrated roofing assemblyaccording to claim 1 wherein said ceiling tiles are plaster ceilingtiles supported by said suspended ceiling grid.
 7. An integrated roofingassembly according to claim 1 wherein said assembly has a pitch of lessthan 10 degrees when fully assembled and installed.
 8. An integratedroofing assembly according to claim 1 wherein the assembly furtherincludes electrical wiring, lights, gutters, skylights, vents, fascias,insulation and ducting.
 9. An integrated roofing assembly according toclaim 1 further including transportable lifting means, wherein saidtransportable lifting means is one or more chain blocks or mobilecranes.
 10. The integrated roof assembly according to claim 1 whereinsaid primary beams are adapted to extend between at least two verticalload bearing columns, said secondary beams are mounted on top of saidprimary beams, and said ceiling grid is positioned below said primarybeams and suspended from said secondary beams.
 11. The integratedroofing assembly according to claim 1 wherein said ceiling grid includeslighting and ventilation panels, and further including lights, wiring,and ventilation ducts.
 12. The integrated roofing assembly of claim 1 inwhich said secondary beams are positioned on the upper surfaces of saidprimary beams.
 13. The integrated roofing assembly of claim 2 in whichsaid secondary beams are positioned on the upper surfaces of saidprimary beams.
 14. The integrated roofing assembly of claim 3 in whichsaid secondary beams are positioned on the upper surfaces of saidprimary beams.
 15. The integrated roofing assembly of claim 4 in whichsaid secondary beams are positioned on the upper surfaces of saidprimary beams.
 16. The integrated roofing assembly of claim 5 in whichsaid secondary beams are positioned on the upper surfaces of saidprimary beams.
 17. The integrated roofing assembly of claim 8 in whichsaid secondary beams are positioned on the upper surfaces of saidprimary beams.
 18. The integrated roofing assembly of claim 9 in whichsaid secondary beams are positioned on the upper surfaces of saidprimary beams.
 19. The integrated roofing assembly of claim 10 in whichsaid secondary beams are positioned on the upper surfaces of saidprimary beams.
 20. A method of constructing and erecting an integratedroofing assembly, the method comprising the steps of:laying out aceiling grid on the ground; laying out primary beams parallel to eachother on said ceiling grid, with said ceiling grid being located beneathsaid primary beams; installing load bearing columns around the peripheryof said ceiling grid and primary beams, each of said primary beamsadapted to extend between two of said columns; fixing secondary beams tosaid primary beams in a direction transverse thereto to form a frame,said primary and secondary beams acting together to provide structuralsupport for roof cladding members; connecting said ceiling grid to saidsecondary beams; installing electrical wiring and lights; droppingceiling tiles into position on said ceiling grid; preparing liftingpoints on said primary or secondary beams; lifting said roofing assemblyinto position on said load bearing columns using chain blocks or mobilecranes coupled to said lifting points; securing said roofing assembly tosaid load bearing columns; and removing said chain blocks or mobilecranes.
 21. A method according to claim 20 wherein the method furtherincludes the step of bracing said load bearing columns to improve theirload bearing capacity.
 22. A method according to claim 21 wherein themethod includes the steps of fixing roof cladding to the frame,installing insulation and installing gutters, skylights, vents andfascias before the step of lifting the roofing assembly into position.23. A method according to claim 21 including the steps of constructingfoundations, and forming a concrete slab, prior to the step of layingout the ceiling grid.
 24. A method of constructing a building accordingto claim 21 wherein the method includes the following steps prior toconstructing the foundations:testing and assessing a site for theconstruction; preparing the site ready for construction; certifying thesite for particular types of constructions; and maintaining the siteready for construction.
 25. The method of claim 20 in which saidsecondary beams are fixed to the upper surfaces of said primary beams.26. The method of claim 21 in which said secondary beams are fixed tothe upper surfaces of said primary beams.
 27. The method of claim 22 inwhich said secondary beams are fixed to the upper surfaces of saidprimary beams.